Mumps: causes, symptoms, incubation and contagion


Mumps, commonly called by the name of "mumps", is a disease caused by a virus belonging to the genus of Paramyxovirus, member of the gods family Paramyxoviridae.

Mumps is widespread all over the world, it is frequent especially in school-age subjects (5-14 years) but can affect people of any age. While among children it may present an asymptomatic or in any case benign course, among adults even serious complications are observed more frequently. The virus is highly infectious and is transmitted by saliva droplets or nasal secretions. Man is the only natural host of the virus. After entry through the respiratory tract the virus replicates locally, subsequently spreads in the blood (viraemia) and reaches target tissues such as the salivary glands and other sites such as the central nervous system, pancreas, testes and less frequently ovaries, heart, kidneys , liver, joints. The incubation period ranges from 12 to 25 days from contact (on average 16-18 days). The infected person is contagious in the 6 days preceding the onset of symptoms and in the 9 days that follow. Primary infection guarantees permanent immunity.

The disease can have an asymptomatic course or with few symptoms, or manifest prodromes such as fever, malaise, headache and within 24 hours the appearance of typical symptoms: pain in the ears especially near the lobes which is aggravated by chewing movements, unilateral or bilateral swelling (in 70% of cases) in correspondence with the mandibular angle (swelling of the parotid glands) and a bitter taste in the mouth. At the oral cavity the outlet duct of the parotid gland (Stenone's duct) can be red and edematous. The fever resolves within seven days. Rarely, a morbilliform rash may appear. The submandibular glands can also be involved. The complications which can occur are: complications affecting the central nervous system such as meningitis or meningoencephalitis (symptomatic forms in 10-30% of infected subjects), less common are transverse myelitis, facial paralysis, hearing loss (0.5-5 / 100,000 cases of mumps); inflammation of the testicles (orchitis) which can affect up to 50% of post-pubescent males. Orchitis is characterized by fever, nausea, vomiting, pain in the lower abdomen and subsequently rapid swelling of the testicles associated with pain. In half of the cases following inflammation, the testes become atrophic and sterility can occur. Less frequently in post-pubertal females there may be inflammation of the ovaries. Other organs involved are the pancreas (pancreatitis), the thyroid gland (thyroiditis), the joints (arthralgia, arthritis), the heart (myocarditis). Infection during the first trimester of pregnancy is associated with a high percentage of spontaneous abortions (25%), no malformative syndromes associated with infection in pregnancy are described. There diagnosis of mumps is initially a clinical diagnosis. Blood tests show a reduction in white blood cells (leukopenia) with a relative increase in lymphocytes (relative lymphocytosis) and an increase in serum amylase (S-amylase). Amylase (P-amylase) and lipase can be increased in pancreatitis. Confirmation of diagnosis occurs by isolation of the virus from cultures of upper respiratory tract secretions, CSF or urine in the acute phase. The PCR (polymerase chain reaction) on secretions or liquor allows to have a quick confirmation of the diagnosis, however this test is not always available. Confirmation of mumps can also be demonstrated by finding IgM immunoglobulins against the virus, or by a significant increase in IgG antibodies between acute and convalescent serum. Other viruses can cause the parotid glands to swell: parainfluenza virus 1 and 3, influenza A virus, cytomegaolvirus, Epstein-Barr virus, enterovirus, HIV. S. aureus infection can cause unilateral swelling of a gland and can be associated with the discharge of purulent material from the Steno's duct. Non-infectious causes of parotid swelling can be: Steno's duct obstruction, Sjogren's syndrome, systemic lupus erythematosus and tumors. There therapy mumps is symptomatic and consists of the administration of analgesics to reduce pain or antipyretics to control fever. There prevention infection occurs through vaccination. The mumps vaccine is a live-attenuated vaccine, available as a monovalent, trivalent (associated with measles and rubella) or tetravalent (associated with measles, rubella and chickenpox) vaccine. The vaccine is given in two doses, at least 28 days apart. The Italian vaccination calendar currently provides for two doses of tetravalent vaccine (MPRV): the first dose between 12 and 15 months of age, the second dose at 5-6 years of age. However, vaccination is also recommended for children and adults who have not been previously vaccinated. Mild localized reactions such as swelling, pain, redness at the injection site and also fever, mild rash, swelling of the face or back of the neck (6-14 days after infection) may occur following the vaccine. Rare manifestations are seizures secondary to fever, joint pain, thrombocytopenia; severe reactions can be allergic manifestations. Contraindications to the vaccine are: subjects with a severe allergic reaction to the first dose of the vaccine, allergic to neomycin or other components, patients with rare hereditary problems of fructose intolerance, pregnant women (the vaccine must be postponed until after delivery). The vaccinating doctor should be notified if the person has an immune system disease or uses drugs that cause immunosuppression, has a tumor, has a low platelet count, has recently received a blood transfusion, immunoglobulin, or a vaccine (in these cases the vaccine is not performed and / or is postponed). The vaccine induces the appearance of specific antibodies in more than 95% of the vaccinated and confers long-lasting immunity over time.


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